Lua Npc System Error

[PureDarkSlayer]

This error comes up on the console every time a player tries to buy a Manarune from the npc and it still doesnt give it to the player:

[22/04/2011 12:43:42] [Error - Npc interface] 
[22/04/2011 12:43:42] (Unknown script file)
[22/04/2011 12:43:42] Description: 
[22/04/2011 12:43:42] data/npc/lib/npcsystem/modules.lua:1151: bad argument #2 to 'error' (number expected, got string)
[22/04/2011 12:43:43] stack traceback:
[22/04/2011 12:43:43] 	[C]: in function 'error'
[22/04/2011 12:43:43] 	data/npc/lib/npcsystem/modules.lua:1151: in function 'callbackOnBuy'
[22/04/2011 12:43:43] 	data/npc/lib/npcsystem/npchandler.lua:263: in function 'processModuleCallback'
[22/04/2011 12:43:43] 	data/npc/lib/npcsystem/npchandler.lua:440: in function 'onBuy'
[22/04/2011 12:43:43] 	data/npc/lib/npcsystem/modules.lua:1292: in function <data/npc/lib/npcsystem/modules.lua:1291>

Rep to whoever helps as always.

 

[PureDarkSlayer]

Still no help? >.>